Birds excrete uric acid as a semi solid paste because uric acid

  • A. is almost insoluble in water, so very little water is lost
  • B. is highly soluble in water
  • C. is converted to urea in the cloaca
  • D. is released as a gas

Explanation

Precipitating uric acid saves water and keeps the egg clean, since an embryo sealed in a shell cannot dilute soluble wastes. Both advantages explain why birds and reptiles chose this route.

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